The objectives of this core are: (1) To provide KC investigators with access to clinical research populations through ongoing and new liaisons with community and state agencies, diverse clinics, and a host of existing databases. Specifically, the core: - Facilitates access to a variety of clinical settings and serves as a liaison to Kennedy Center related clinics, including the Susan Gray School, Vanderbilt Kennedy Reading Clinic, Vanderbilt Kennedy Behavior Analysis Clinic, Vanderbilt Kennedy Family Outreach Center, and the Vanderbilt Down syndrome Clinic. - Sustains and promotes successful partnerships with community and state disability programs that facilitate research participation. - Facilitates access to existing clinical databases for recruitment and research purposes, identifies new databases for use by KC investigators, and develops and maintains KC databases as needed. (2) To assist investigators with state-of-the-art psychological and behavioral assessments, which contribute to the broader gene-brain-behavior research agenda of KC investigators. Specifically, the core: - Assists investigators with training and administration of standardized neuropsychological, psychiatric, psychosocial, and educational assessments, especially in highly researched populations (e.g., autism, Down Syndrome). - Broadens the scope of behavioral domains within assessments. - Develops novel assessments as needed. - Contributes to the literature on assessment of persons with mental retardation.